Black''''s veterinary dictionary 21st edition - N potx

N Nagana Nagana is an unscientific but convenient name for trypanosomiasis transmitted by tsetse flies (Glossina spp.) in Africa The trypanosomes involved are Trypanosoma vivax, T uniforme, T congolense, T brucei, T simiae, and T suis (See TRYPANOSOMES.) The symptoms of nagana include anaemia, intermittent fever, and (except in pigs, in which the disease may be very acute) a slow, progressive emaciation In both horses and dogs the eyes may be affected, as shown by corneal opacity Horses often have oedema affecting the limbs and abdomen Cattle may abort The drug quinapyramine is used (among others) in treatment The kudu, hyena, and bush-buck, as well as other wild animals, act as reservoirs of the infection Nail Binding (see INJURIES FROM SHOEING) Nails (Claws) A claw contains a matrix with blood vessels, nerves, etc., from which it grows and is nourished Lying within the matrix is the bone of the terminal phalanx of the digit, which gives the nail its characteristic form in the different animals When not in use in the carnivora, nails are retracted by ligaments in an upwards direction; this is more marked in cats, where the nail may almost disappear, than in dogs Nails, Diseases of The nails of cats and dogs sometimes become torn or broken through fighting or accidents Sometimes only the tip is injured, and the matrix higher up is undamaged; in such cases a fine pellicle of horn covers the tip until such time as the horn has grown down from above, and the whole nail is not shed In other cases infection occurs, causing great tenderness of the part Ingrowing nails occur upon the ‘dew claws’, on the insides of the paws of dogs These more or less rudimentary digits not touch the ground, and are consequently not subjected to wear from friction The nails grow, and owing to their curve eventually penetrate the soft pad behind them Where actual penetration has occurred, the nail should be cut short and an antiseptic dressing applied It is customary for owners of sporting and other dogs to have the dew claws removed during puppyhood to avoid future trouble of this nature Amputation of dew claws can be carried out in the adult under anaesthesia Onychomycosis, or a fungal infection of the claws, is a not uncommon condition in cats, and is of public-health importance as a reservoir of ringworm transmissible to children (See RINGWORM.) Nairobi Sheep Disease Nairobi sheep disease is an acute infectious fever of sheep and goats, caused by a bunyavirus, and occurring in eastern and southern Africa The virus is transmitted by the tick Rhipicephalus appendiculatus Signs Imported sheep usually show an acute febrile disturbance within or days after being infected by the ticks This lasts for up to days and then a fall in temperature occurs and other clinical symptoms appear Death may take place a day or two later, or a further rise in temperature may be shown, death or recovery following There is rapidity and difficulty in breathing, a mucopurulent nasal discharge and green watery diarrhoea, which may contain mucus or blood The genital organs of ewes are swollen and congested, and abortion may occur in pregnant ewes Immunity In the great majority of cases, recovery confers a strong and lasting immunity This is also possessed by sheep in areas where the infection is endemic Nanogram (ng) A unit of weight equivalent to 1000 micrograms µ 1000 micrograms equal milligram (mg) Nanometre (nm) A unit of linear measurement used in e.g virology One nm equals one millionth of a millimetre Naphthalene Poisoning Naphthalene poisoning might arise from the ingestion of moth-balls In the dog, it has been shown experimentally to give rise to haemolytic anaemia (In children, poisoning from mothballs gives rise to ‘port-wine coloured’ urine.) Another symptom is cataract Chlorinated naphthalenes have been identified as one cause 480 Narcolepsy of HYPERKERATOSIS in cattle; and tear stains may be a symptom of this type of poisoning Narcolepsy Narcolepsy is a sudden collapse into deep sleep It has been recorded in dogs, and may be partly genetic in origin A case was recorded in the UK in a 3-year-old Corgi which sometimes collapsed when taken for his first walk of the day, or offered food Often yawning and a vacant expression would precede a sudden drop from a standing position to a sitting one or a lying one No excitement, salivation, or convulsions were seen, and at other times the dog was active and mentally alert; he was easily aroused after he had collapsed Electro-encephalograms supported the diagnosis The condition has also been recorded in daschunds, dobermanns, labradors and poodles Nares Nares is the Latin word for the nostrils Nasal Bot Fly (Oestrus Ovis) Larvae Nasal Bot Fly (Oestrus Ovis) Larvae are serious parasites of sheep (See under FLIES.) Nasal Disorders N (see NOSE & NASAL PASSAGES, DISEASES OF) Naso-Oesophageal Tubes Narrow tubes inserted through the nose into the stomach They are tolerated by many, if not most, cats, and can be used to provide nutritional support via liquid foods for a week or two The use of small-diameter tubes does not prevent voluntary intake of food Naso-Pharynx The upper part of the throat lying posterior to the nasal cavity Natamycin An antibiotic used for the treatment of ringworm in cattle and horses Application can be made with a knapsack sprayer (See RINGWORM.) National Scrapie Plan A long-term UK plan which aims to reduce and, eventually, eradicate the number of sheep not genetically resistant to scrapie and other transmissible spongiform encephalopathies Under the scheme, sheep are individually identified by electronic tag, and blood-tested to establish whether they are susceptible or resistant to scrapie Sheep identified as susceptible must not be bred from Under DEFRA proposals in 2003, farmers with confirmed scrapie cases on their farms will have their flocks genotyped so that the more susceptible sheep can be identified and removed, or the whole flock disposed of National Office of Animal Health (NOAH) Founded in 1986, to represent those UK companies which manufacture animal-health products licensed under the Medicines Act Address: Crossfield Chambers, Gladbeck Way, Enfield, Middlesex EN2 7HF Publications include: The Safe Storage & Handling of Animal Medicines; Poisoning in Veterinary Practice National Pet Register This provides a service for reuniting lost pets with their owners, and also for third-party liability Address: Heydon, Royston, Herts SG8 8PN Nature Oedema of the udder (see under OEDEMA) Navel-Ill (see JOINT-ILL) Navicular Bone Navicular bone is the popular name for the sesamoid of the 3rd phalanx of the horse It is a little boat-shaped bone, developed just above the deep flexor tendon, and serves, as all sesamoid bones, to minimise friction where the tendon passes round a corner of another bone It enters into the formation of the ‘coffin-joint’, between the 2nd and 3rd phalanges of the digit It is of great importance in deep punctured wounds of the foot when these are situated towards the heels, for, when damaged, its surface becomes inflamed, the inflammation spreads to the coffin-joint and may produce incurable lameness Navicular Disease Navicular disease is a chronic condition of inflammation affecting the horse’s navicular bone and its associated structures The fore-feet are usually both attacked, though the condition may arise in only one of these, or in the hindfeet (rarely) Ulceration of the cartilage first, and later of the bone on the surface over which the deep flexor tendon plays, may sometimes be seen at autopsy Causes These are still a matter of hypothesis rather than certainty, and controversy persists Necrosis (Bacillary) or Necrobacillosis Some authors have referred to increased vascularisation of the navicular bone; others suggest that ischaemia may be responsible, leading to pain and, if at least of the distal arteries are occluded, to chronic lameness In horses lame as a result of navicular disease, occlusion of the main artery and progressive arterial thrombosis are frequent, with a resulting area of ischaemic necrosis and cavitation of the navicular bone Another view is that the disease is not caused primarily by ischaemia and subsequent necrosis, but is a consequence of bone remodelling due to altered pressure from the deep flexor tendon and increased load on the caudal part of the foot – the condition not being irreversible unless secondary lesions such as adhesions and bony spurs have developed Special shoeing to alter the load on the navicular bone is recommended Signs Navicular disease usually develops so slowly that the owner has considerable difficulty in remembering exactly when the first symptoms were noticed In fact, little or no importance may be attached to the almost characteristic ‘pointing’ of one or both fore-feet, because ‘he has always done that’ ‘Pointing’ consists of resting the affected foot (or feet) by placing it a short distance in advance of the other when standing in harness or in the stable When both feet are affected, each is alternately pointed Later, the horse may go lame or be tender on his feet at times, but with a rest he generally becomes sound again As the disease advances, he may either start off in the mornings stiff and become better with exercise as he warms to his work, or may become lame as the day goes on Sooner or later, however, there comes a time when he will go permanently ‘pottery’, or ‘groggy’ The length of the stride decreases and there is difficulty in advancing the feet, so it looks as if the shoulder is the seat of the lesion When made to turn, the horse pivots round on the fore-feet instead of lifting them, and when made to back, drags the toes If the shoe of such a horse is examined it is usually found to be more worn at the toes than at the heels In fact a ‘groggy’ horse may wear his shoes quite thin at the toes before the heels show much sign of wear at all In the final stages the horse becomes distinctly lame and unfit for work When observed in the stable he is noticed to be continually shifting from one foot on to the other, and the resting foot is placed well out in front 481 vasodilator isoxuprine or a formulation of warfarin may be added to the feed of horses; the dosage of warfarin requires great care – with overdosage there is a danger of haemorrhage Warfarin treatment has been reported effective in about 75 per cent of cases of navicular disease Before the advent of drug therapy it was customary to perform the operation of neurectomy, which consists of a section of the plantar or median nerve of the limb In a favourable case, following operation, the horse becomes apparently sound, although the diseased condition is still at work in the bone No pain is felt, and the horse is fit for light work at slow paces The feet require constant attention to ensure that no stones, nails, etc lodge in the hoof, for even when these inflict serious damage the horse still goes sound, not feeling the pain Navy Beans Navy beans may cause death if fed raw (See LEGUME POISONING.) Near East Encephalitis An alphavirus infection of horses and donkeys; less frequently of cattle and sheep Convulsions/paralysis may follow fever and precede death (See EQUINE ENCEPHALITIS; BORNA DISEASE.) Neck In animals, the neck is that part of the body connecting the head with the trunk It contains the trachea, oesophagus, blood vessels, the spinal cord and cervical vertebrae Both the mouse and giraffe have cervical vertebrae, as most mammals The weight of the head is supported by the powerful ligamentum nuchae, which takes the strain off the muscles, thereby avoiding fatigue In the horse the ligament extends from the spines of the withers to the posterior of the occipital bone of the SKULL Necrobacillosis Damage of an organ, or tissue, caused by Fusobacterium necrophorum The necrotic area has a characteristic rotting odour Necropsy Examination of a dead body (see AUTOPSY) Necrosis Death of cells or of a limited portion of tissue Treatment must aim at the relief of pain and Necrosis (Bacillary) or Necrobacillosis improvement of the local blood circulation The (see CALF DIPHTHERIA) N 482 Necrotic Enteritis Necrotic Enteritis Nematodiriasis A subacute or chronic enteritis which follows a more severe episode caused by infection with Salmonella spp or Campylobacter sputorum var mucosalis A condition of unweaned and older pigs, characterised by scouring and loss of condition The lesions are in the caecum and ileum (See also under ILEUM.) Cold, damp, dirty surroundings appear to predispose to necrotic enteritis (See PORCINE INTESTINAL ADENOMATOSIS.) Infestation of the intestine or abomasum of ruminants by Nematodirus species It is endemic in some parts of the UK Disease develops suddenly and leads to dullness and loss of condition, with black diarrhoea and dehydration; in lambs, death may follow in a few days Necrotic Enteritis in Chickens A disease of chickens characterised by unthriftiness and diarrheoa caused by Clostridium perfringens (welchii) type C There is usually a concurrent defect in nutrition The disease has been reported in most European and North American countries, and in Australia Necrotic Stomatitis A serious infection of the inside of the mouth and the tongue, seen in calves; it may also be found in reptiles (See CALF DIPHTHERIA.) Negri Bodies N Negri bodies are comparatively large, rounded bodies in the brain cells of animals infected with rabies Their presence can be demonstrated by staining with Seller’s stain, among others The cerebral cortex, Ammon’s horn, and the Purkinje cells of the cerebellum are the main sites to examine The diagnosis of rabies once depended upon the demonstration of Negri bodies in the affected animal (See RABIES.) Neisseria Spherical, Gram-negative bacteria, some of which are associated with eye infections Nematocide A drug that destroys nematodes Nematode Prevention As the eggs can survive over winter, the life-cycle can be broken by not using the same lambing ground in successive seasons Routine dosing of lambs in susceptible areas can be effective Nematodirus Parasitic worms of, particularly, lambs; also sheep and calves N battus infection is transferred from one season’s lambs to the next as large numbers of eggs are deposited on pasture Development of the eggs occurs only after exposure to cold and moisture (See WORMS.) Nembutal (see PENTOBARBITONE SODIUM) Neoarsphenamine A drug effective against BLACKHEAD OF TURKEYS It has been largely superseded by dimetridazole and nifursol Neomycin An aminoglycoside antibiotic obtained from Streptomyces fradiae It must not be given by injection, owing to resulting kidney damage Its action closely resembles that of streptomycin It is used, sometimes in combination with other medicaments, in a number of veterinary formulations A topical spray of this antibiotic has caused profound deafness in children (See DEAFNESS.) Neonatal Neonatal diseases are those of the newborn Nematode is a general term applied to the parasitic Nemathelminthes, which include the roundworms, as distinct from the Platyhelminthes, or flatworms (See WORMS.) Neoplasm ‘Nematode Poisoning’ This parasite was discovered in Norway in 1984, and later recognised in Sweden, the USA, Australia, and the UK in 1990 In the USA, larvae of Anguina agrostis on Chewing’s fescue in immature hay caused an outbreak of poisoning in cattle Symptoms included knuckling of the fetlocks, head tucked between the fore-legs, recumbency, convulsions, and death Neoplasm means literally ‘a new growth’, and is applied to tumours in general Neospora Caninum Cause A protozoan, named as above, and resembling Toxoplasma gondii Congenital infection occurs in cattle, dogs, and cats Nerves, Injuries to Signs Infected animals may develop ataxia, a fleeting paralysis, and nystagmus Meningitis appears in some cases The parasite may also be found in aborted ovine fetuses Neoteny The retention of juvenile activities and appearance into adulthood It is the basis of popularity of some breeds of dog that remain as playful as puppies throughout their life The extreme example is an amphibian, the axolotl or Mexican walking fish, which rarely matures to the adult stage Nephrectomy Nephrectomy is the name given to the operation by which one of the kidneys is removed (See KIDNEY, DISEASES OF.) Nephritis Inflammation of the kidneys (see DISEASES OF; LEPTOSPIROSIS) KIDNEY, Nephrolithiasis The presence of a stone (calculus) in the pelvis of the kidney Nephron The structural unit of the kidney (see KIDNEYS) Nephroptosis ‘Floating kidney’ – abnormal positioning of the kidney (see KIDNEY, DISEASES OF) Nephrosis This is a disease of the kidneys, involving damage to the tubules It leads to albuminuria and often to oedema (See also KIDNEY, DISEASES OF.) Nephrosis, Infectious Avian A disease of chickens (See GUMBORO DISEASE; INFECTIOUS BURSAL DISEASE.) Nephrotic Syndrome (see NEPHROSIS) Nephrotomy Surgical incision into a kidney Nerve Block Anaesthesia of a nerve or nerves supplying part of the body to assist diagnosis or treatment Often used in diagnosing the cause of lameness in the horse Nerves The nerves are fibre-like tissues that convey impulses (‘messages’) between the central 483 nervous system and other parts of the body The basic unit of the nervous system is the neuron, a cell with at least projection Bipolar neurons have long projection, the axon, and short branching projection, the dendrite A typical neuron (multipolar) has several dendrites but usually only axon (nerve fibre) Dendrites conduct nerve impulses towards the nerve cell; axons conduct away from it A synapse is a point or area where neuron is able to make contact with another; the contact being between the axon of neuron and a dendrite of another neuron, or between the axon of neuron and the cell of another neuron Any neuron may connect with axons or dendrites of several other neurons Nerve fibres may be myelinated (enclosed in a sheath) or unmyelinated (see MYELIN) Some nerve fibres (axons) convey impulses to brain or spinal cord from skin or sense organ, and are termed sensory or afferent Their impulses are passed, through connecting links or interneurons, to motor or efferent nerves from brain or spinal cord (but see spinal reflex under SPINAL CORD – Functions) Nerve impulses are dependent upon the permeability of cell membranes There is a potential difference of about 70 to 80 millivolts between the inside and the outside of an axon – the inside being the negative This is owing to the fact that in a resting state the cell membrane is permeable to K(+) and Cl(–) ions, but not to Na(+) ions Stimulation of the nerve results in the membrane becoming permeable to the sodium ions, which flow in causing the inside of the axon to carry a positive electrical charge instead of a negative one A so-called depolarisation wave is set up, ‘self-perpetuating’, along neuron after another A single nerve fibre can send about 1000 separate impulses per second ACETYLCHOLINE is released by somatic (muscle) nerve fibres at synapses between neurons on either side of ganglia, and also at the junction of motor nerve endings and voluntary (striated) muscle Acetylcholine is released also at synapses by parasympathetic nerve fibres NORADRENALIN is released at synapses of sympathetic nerve fibres, and at their junction with smooth (unstriated) involuntary muscle fibres Nerves, Injuries to Continued or repeated severe pressure upon a nerve trunk may be sufficient to damage it and result in paralysis; severe bruising in which a nerve is driven against a bone with considerable force may produce paralysis or inflammation of the nerve; a nerve may be severed along with N 484 Nervous System other tissues in a deep wound; fracture of a bone, such as the 1st rib, may produce rupture of any nerves that lie upon or near to it; and other accidents may also involve the nerves of the part A nerve may sometimes be injured at its origin before it leaves the brain or spinal cord by haemorrhage (See also under IMMUNISATION.) Signs Sometimes, it is not until after a wound has healed that the injury to the nerve becomes obvious In ‘radial paralysis’, or in other cases where large and important motor nerves have been damaged, the resulting paralysis of the muscles they supply is seen at once (See RADIAL PARALYSIS.) Atrophy of muscles results (See FACIAL PARALYSIS for another example of a nerve injury.) A tumour, such as a neurofibrosarcoma or (in the cat) a lymphosarcoma, may press upon or infiltrate the brachial plexus causing progressive lameness and pain (See BRACHIAL.) Another tumour is a NEUROMA If a nerve is cut, the distal part degenerates This is called Wallerian degeneration Neuritis (see under this heading) Nervous System Neuroglia A fine web of tissue and branching cells which supports the nerve fibres and cells of the nervous system Neuroleptanalgesia A state of combined sedation and analgesia It is used for carrying out minor surgical procedures where full anaesthesia is not required A combination of a sedative, e.g acepromazine, and a powerful analgesic, e.g pethidine, is used Neuroma A tumour connected with a nerve, and very painful Neuron Neuron is a single unit of the nervous system, consisting of nerve cell, with all its processes (See illustration and also NERVES.) Neurotropic Virus Neurotropic virus is one which shows a predilection for becoming localised in, and fixing itself to, nerve tissues The best known of these is that of rabies Rabies virus enters the body through torn nerve fibres at the seat of an (see CENTRAL NERVOUS SYSTEM) N Nervous System, Diseases of (see BRAIN, DISEASES OF; ENCEPHALITIS; BOTULISM; CHOREA; DISTEMPER; CANINE VIRAL HEPATITIS; TETANUS; RABIES; SPINAL CORD; LISTERIOSIS; etc.) Nettle-Rash (see URTICARIA) Neurectomy Neurectomy is an operation in which part of a nerve is excised The operation is sometimes performed to give relief from incurable lameness in the horse, but only a few months’ work may be gained Neurilemma Neurilemma is the thin membranous covering of nerve fibres Neuritis Inflammation affecting nerves or their sheaths It is often accompanied by pain (neuralgia), sometimes by spastic paralysis Causes include viral infections, allergies, malnutrition, and poisoning, as well as physical injuries (See NEUROMA; NERVES, INJURIES TO; and under IMMUNISATION.) A typical neuron: A – dentrites, B – nerve cell body, C – nucleus, and D – axon (After Francis, Introduction to Human Anatomy, courtesy of C V Mosby Co.) Nicking injury, such as a bite, and, growing along them, eventually reaches the spinal cord and brain Other neurotropic viruses are those of loupingill in sheep, and Borna disease in horses and cattle Neutering (see CASTRATION and SPAYING; also VASECTOMY) Neutrons Elementary particles with approximately the same mass as a proton The latter has been defined as a stable, positively charged elementary particle found in atomic nuclei in numbers equal to its atomic number Neutropenia A reduced number of neutrophil granular leukocytes in the blood (In human medicine, most cases are attributed to the direct toxic effect of certain antibiotics, e.g penicillin and the cephalosporins, or to immune-mediated mechanisms With this type of blood dyscrasia patients are at serious risk of an overwhelming infection.) Neutrophil A type of white blood cell which can migrate into the tissues and engulf bacteria, etc (See under BLOOD; ABSCESS.) New Forest Disease (Infectious Bovine Keratitis) A painful eye condition which can lead to blindness if neglected (See EYE, DISEASES OF.) New Forest Fly A blood-sucking fly, found in many parts of Britain Hippobosca equina attacks horses and cattle It deposits larvae (not eggs) in the soil When disturbed, it makes a characteristic sideways movement (See FLIES.) 485 pale, misshapen and/or soft-shelled eggs According to the virus strain, infected birds develop respiratory or nervous signs; it is rare to find both together Severe breathing difficulties develop in birds affected with the respiratory strain In the nervous form, torticollis, paralysis of the wings or legs and impaction of the intestine are features In mild cases, the main clinical sign may be diarrhoea, usually black Mortality varies Egg production may recover, but not to its former level Control Live and inactivated vaccines are used Vaccination regimes can vary according to local circumstances and must be established on the basis of veterinary advice; the manufacturer may need to be consulted Live vaccines include the Hitchner B1; they are administered in the drinking water, by beak-dipping, by eyedropper or by aerosol spray The manufacturer’s directions must be strictly followed in each case The inactivated vaccine is used for secondary vaccination after primary immunisation with live vaccine It is administered intramuscularly into the thigh muscle or subcutaneously into the back of the neck It should always be assumed that, in the vicinity of an outbreak, every flock to be vaccinated is incubating the disease The incubation period is around 21 days and it takes 10 to 14 days to build up an immunity Newfoundland A large breed of dog developed in Canada to rescue people from rivers and the sea; it is a powerful swimmer It is long-haired and usually black or brown Hip dysplasia, aortic stenosis, ununited anconeal process and osteochondritis may be inherited ‘Newmarket Cough’ (see EQUINE INFLUENZA; COUGH) Newcastle Disease Niacin (Nicotinic Acid) An infectious, febrile notifiable disease of chickens, turkeys, ducks, pigeons and wild birds Globally, it is the most economically important disease of livestock Aviary birds, particularly finches (canaries, etc.), may be infected by wind spread Waterfowl can be infected but clinical disease is rare In humans, conjunctivitis is the main clinical sign, but people working with infected birds may develop an influenza-like illness One of the vitamin B group, present in most animal feeds, and produced in the digestive system from tryptophan With maize feeding, a niacin deficiency may occur It has been suggested that niacin supplements benefit dairy cows, as synthesis of the vitamin in the rumen may not be sufficient, which was formerly thought to be the case In dogs a niacin deficiency causes ’BLACK TONGUE‘ (See SHEEPDOGS; VITAMINS.) Cause Paramyxovirus Signs The first sign noticed in laying birds may be a drop in egg yield with the production of Nicking This is defined in the Docking and Nicking of Horses Act 1949 as ‘the deliberate severing of N 486 Nicotine Poisoning any tendon or muscle in the tail of a horse’ The practice is illegal (See GARDEN NIGHTSHADE POISONING; BITTERSWEET; and ATROPINE POISONING) Nicotine Poisoning Nigroid Bodies Nicotine poisoning has killed cattle dressed with nicotine against warbles, and may also arise from the old practice by shepherds of dosing their flocks with tobacco against parasitic worms Poisoning has also been reported in poultry when perches have been painted with nicotine sulphate to try to control red mite (Dermanyssus galinae) Nigroid bodies are black or brown irregular outgrowths from the edges of the iris of the horse’s eye (See IRIS.) Nicotinic Acid One of the vitamin B group present naturally in the body and convertible to NIACIN Nictitating Membrane The ‘3rd eyelid’, or haw, consists of a plate of cartilage covered with conjunctiva, and having lymphatic tissue and the Harderian gland Often pigmented, the membrane is always prominent in breeds of dogs such as the bloodhound and St Bernard In other breeds of dog, and in the cat, its protrusion across part of the eye may indicate general debility if bilateral; other causes include the presence of a foreign body, ulceration, a nerve injury, or occasionally a tumour N ‘Night Blindness’ ‘Night blindness’ is seen in vitamin A deficiency and early progressive retinal atrophy (see EYE, DISEASES OF) NIGHT LIGHTING Night lighting is commonly practised in poultry houses, using 40-watt lamps to give a 14-hour day, or 1500-watt lamps for three 20-second exposures a night The object is increased egg production during the winter months, and the effect is due not merely to the provision of extra feeding-time, but also to the influence of light indirectly on the ovaries However, an investigation carried out in conjunction with the ADAS into eye abnormalities in turkey breeding flocks, leading to blindness, showed that the cause was continuous artificial light Seventy per cent of poults showed symptoms after weeks of this, and it was proved that it was the continuity and not the intensity of the light which was doing the damage NIGHTSHADE POISONING The nightshades comprise garden or black nightshade (Solanum nigrum), woody nightshade or bittersweet (S dulcamara), and deadly nightshade or belladonna (Atropa belladonna) Nipah Virus Nipah virus is responsible for a disease of pigs in tropical areas It causes fever, nervous signs, respiratory difficulties and abortions An outbreak of encephalitis among pig farmers in Malaysia, caused by the virus, resulted in the slaughter of 1.1 million pigs (out of a total pig population of 2.4 million) on 956 farms in an effort to control the outreak Only 796 pig farms remained Of 256 people who suffered from encephalitis, 105 died The infection is thought to have originated in flying foxes Nipple-Drinkers Nipple-drinkers are popular in pig and poultry enterprises as they supply water on demand without using troughs, and avoiding the possiblity of drinking water being fouled Similar drinkers are available for use by dogs in kennels Animals may have to be taught how to use them Nipples Infection and necrosis of sows’ nipples are not uncommonly caused by Fusiformis netrophorus, and may lead to the death of piglets from starvation (See also MAMILLA – Mamillitis.) Nit Egg of louse or other parasitic insect Nitrite Poisoning Poisoning as a result of eating plants with a high potassium nitrate content is common in some of the western parts of the USA The nitrate is reduced to nitrite by substances within the plant under certain climatic conditions, and when such a plant is eaten the nitrite is rapidly absorbed from the digestive system and converts haemoglobin into methaemoglobin This is incapable of giving up its oxygen to the tissues and as a result the animal dies Sodium nitrite is used for curing meat and has found its way into swill, causing fatal poisoning in pigs The main symptoms observed were vomiting, squealing, and distressed breathing Nitrite poisoning has also occurred, in piggeries with poor ventilation, from condensation dripping down It may arise, too, in grazing animals where nitrogenous fertilisers Noah have been spread during dry weather, or before rain has had time to wash it all in This could be called nitrate poisoning, but the nitrate itself has a fairly low toxicity, being converted into the poisonous nitrite The nitrate content of heavily fertilised plants may increase the animal’s intake of nitrates Treatment consists of methylene blue intravenously, and ascorbic acid (See NITROSAMINES.) Signs include abdominal pain, sometimes diarrhoea, weakness and ataxia, dyspnoea, rapid heart action and, especially, cyanosis The mucous membranes appear brown, due to the presence of methaemoglobin Convulsions, coma, and death may follow In a case reported by the State Veterinary Service, acute poisoning was seen in 13 cows after they had been brought into a shed An hour or two later, were dead, were dying and were very distressed, showing dyspnoea, salivation, cramping pains and head-pressing Their blood was dark brown The local hospital was asked to make up a per cent solution of methylene blue, which they did within 15 minutes When each cow was injected intravenously with 500 ml, the response was dramatic and reminiscent of that seen in the successful treatment of milk fever with calcium Sequelae of this event were abortion in of the cows and a change in temperament, normally quiet cows becoming wild The source of the nitrate was believed to be straw bedding contaminated with fertiliser from broken bags Fatal nitrite poisoning of pigs has occurred following the use, for drinking purposes, of rainwater containing decaying organic matter Nitrites Nitrites are salts which, in excess, convert haemoglobin into methaemoglobin, and may cause death from lack of oxygen (See NITRITE POISONING; NITROSAMINES.) Nitrofurans A group of drugs developed in the USA during the 1940s, and including nitrofurazone, furazolidone, and nitrofurantoin (for urinary tract infections) They are effective against a wide range of bacteria, including Gram-negative; some against protozoa and fungi It is thought that they interfere with the carbohydrate metabolism of micro-organisms The use of furazolidone and nitrofurantoin for medicines in food-producing animals is prohibited in the EU 487 Nitrogen (see AIR) For liquid nitrogen see CRYOSURGERY; ARTIFICIAL INSEMINATION; LIFE AFTER FREEZING Nitrogen dioxide A reddish-brown heavy gas with an offensive odour This is formed by oxidation, on exposure to air, from the colourless nitric oxide The latter appears to be the chief oxide of nitrogen produced in the early stages of silage-making Emissions of this gas from silage clamps have caused human illness and the death of farm animals Signs Dyspnoea, cyanosis, muscular weakness and, in piglets, vomiting Nitrophenide Poisoning Nitrophenide poisoning, characterised by paralysis, has occurred in pigs fed medicated meal intended for poultry and containing nitrophenide as a treatment for coccidiosis Nitrosamines They are very powerful chemical carcinogens They cause cancer of specific organs irrespective of the route of administration Some nitrosamines can be formed from nitrite and secondary amine or amide in the acid stomach contents of animals Nitrites used as food preservatives, and high levels of nitrates in drinking water, can be carcinogens Nitroscanate A general anthelmintic for use in dogs It acts against both tapeworms and roundworms Nitrothiazole The drug 2-amino-5-nitrothiazole is effective in controlling blackhead in turkeys (by preventive medication) Nitrous Oxide This anaesthetic is not much used in veterinary practice but, where it is, there is a need for good ventilation, as it interferes with vitamin B metabolism and, in a pregnant anaesthetist, may bring about a miscarriage Nitroxynil Nitroxynil, a fasciolicide, is used by injection for the treatment of fluke in cattle and sheep and, given by mouth, against gapeworm in birds Animals must not be slaughtered for meat until 30 days after administration NOAH (see NATIONAL OFFICE OF ANIMAL HEALTH) N 488 Nocardiosis Nocardiosis Nose and Nasal Passages Infection with Nocardia asteroides in cattle, dogs, cats, and man It is a saprophytic inhabitant of the soil and belongs to the genus Actinomycetes It was formerly classified as a fungus but is now regarded as a bacterium It has occasionally been isolated from the udders of cows affected with mastitis, and has been reported as the cause of ‘incurable mastitis’ in an outbreak on a Texas farm Involvement of the liver and mesentery, with marked loss of condition, thirst, and some diarrhoea – calling for euthanasia – has been recorded in the dog in Britain Pleuropneumonia, occasionally also a skin infection, may result from Nocardia in dogs and cats The ‘nose’ of an animal, which is more often termed the ‘muzzle’, or ‘snout’, according to the species, serves important functions It forms the outermost end of the respiratory passage; it is the organ of smell; and it contains some of the end-organs of the sense of touch Node (see LYMPH NODES) Nodular Panniculitis An inflammatory reaction involving subcutaneous fat, and characterised by nodules which burst Abscesses and sloughing may occur (See AUTO-IMMUNE DISEASE, of which the above is an example, occurring in dogs.) Noise (see STRESS) N Noradrenalin A hormone secreted by the adrenal gland medulla It causes increased heart rate, and constricts the blood vessels, causing a rise in blood pressure (See NERVES.) Normal Saline (Physiological Saline) Normal saline (Physiological saline) is a solution of sodium chloride in sterile distilled water, which is isotonic with the strength of this salt in the bloodstream – that is, about 0.9 per cent for mammals (See also DEHYDRATION; DEXTRAN.) Normoblast Normoblast is a red blood cell which still contains the remnant of a nucleus Northern Fowl Mite This can infect canaries as well as poultry, and has caused allergic reactions in poultry-keepers in Israel (See MITES.) Norwegian Scabies This is a form of sarcoptic mange The skin becomes red, the hair falls out in patches, and there is intense pruritus Horses Externally, the rims of the nostrils are built up on a basis of cartilages covered over by a fold of delicate skin possessing long tactile hairs The cartilages are not complete laterally, thereby allowing the nostrils to become greatly distended during occasions of emergency Situated at the upper and outer part of each nostril there is a pouch-like sac which opens into the nostril at one end, but is blind at the other This is often called the ‘false nostril’ Lying just within the entrance to the nasal passages about an inch or so inside each nostril is the lowermost opening of the lacrimal duct carrying tears secreted by the lacrimal gland of the eye Internally, each nostril, and the nasal passage to which it gives access, is completely divided from the other by the septum of the nose and its associated structures This is composed partly by the vomer bone, and partly by a wall of cartilage which is continuous with the cartilages of the nostrils The walls of each passage are lined by mucous membrane which is reflected on to the two turbinated scroll-like bones that are found in the passage; this membrane, being well supplied with blood, and being continually moist from the secretion of its mucin glands, serves to warm and moisten the incoming air before it passes to the lungs, and to extract the larger particles of dust, soot, etc., that the air picks up, by causing them to adhere to its sticky surface The entrance to the air sinuses of the skull leads out from the posterior part of each passage, the mucous membrane lining the sinuses being continuous with that of the nose (See SINUSES OF THE SKULL.) The end-organs of the sense of smell are scattered throughout the nasal mucous membrane in the upper parts particularly The olfactory nerves from the brain, which pass out of the cranial cavity into that of the nose by way of the ethmoid bone, are distributed to these end-organs Posteriorly, the nasal passages lead into the pharynx Cattle The nostrils, situated on either side of the broad expanse of moist hairless muzzle, are smaller and thicker than in the horse No false nostril is present, and the opening of the lacrimal duct is not visible Notifiable Diseases Nose and Nasal Passages, Diseases of Catarrh Inflammation of the nostrils is called RHINITIS, and may accompany ordinary catarrhal inflammation of the nasal passages such as occurs in cases of distemper in the dog, of other febrile illnesses The symptoms often resemble those of a human ‘cold in the head’, with a discharge from the nostrils which is at first clear and colourless, later becoming thick and yellowish-green Horses and cattle often snort and shake their heads; dogs sneeze Conjunctivitis may accompany the nasal catarrh In horses, the presence of ulcers in the mucous membrane with a punched-out appearance may indicate GLANDERS For a specific condition in the pig, see ATROPHIC RHINITIS Parasites, such as larvae of the sheep-nostril fly, Linguatula, or leeches in dog or cat, may cause a discharge from one or both nostrils A discharge from nostril only may in the dog, for example, indicate the presence of a FOREIGN BODY such as a grass awn; or there may be a fungal infection (e.g ASPERGILLOSIS) which may follow local injury or tumour formation Another possible cause is an abscess at the root of a tooth, with pus collecting in the maxillary sinus and escaping through the nasomaxillary opening Treatment Nasal catarrh should be considered contagious The animal should be isolated accordingly, and attention paid to comfort, ventilation, and suitability of food, as discussed under NURSING OF SICK ANIMALS Symptoms of other diseases must be looked for, especially when the temperature is high, and a professional diagnosis should be obtained The nostrils should be kept moist and pliable by rubbing small quantities of Vaseline around their rims daily, after sponging away discharges Diseased conditions of the turbinated bones or of the molar teeth call for surgical measures for their correction; parasites in the nasal cavities must be expelled (see MITES); and if other foreign bodies are present they must be removed Haemorrhage from the nostrils may be due to injuries which cause tearing or laceration of the mucous membrane; it may occur during violent exertion, such as racing or hunting with horses not in maximum condition; it may be associated with ulceration, congestion, tumour formation, or other diseased condition of the nasal mucous membrane; it may be due to 489 fracture of a horn core in cattle and sheep, the blood entering the nose from the sinuses of the skull; in horses it may be seen in GUTTURAL POUCH DISEASE; and see ‘BLEEDER HORSES‘ When the haemorrhage is only slight, little more than keeping the animal quiet, and applying douches of cold water to the bridge of the nose, will be required A thin trickle of blood coming from nostril only can be disregarded, as it will generally cease of its own accord When the bleeding is very profuse, and there may be danger of collapse, more drastic measures are needed Where only nostril is affected it should be plugged with swabs of cotton-wool enclosed in gauze, and so arranged that some of the gauze is left outside the nostril to allow of removal some hours afterwards In horses, care must be taken not to confuse nose bleeding with pulmonary bleeding Severe bleeding from both nostrils requires veterinary intervention; both nostrils may need to be plugged after first having performed a tracheotomy Tumours include polyps, especially in the cat; and adenocarcinoma in dogs and other animals Among other conditions in which the nose or the nasal passages are affected may be mentioned: fungal infections, TUMOURS, mucosal disease, malignant catarrh, GLANDERS, URTICARIA, PURPURA HAEMORRHAGICA, STRANGLES, and INFLUENZA (See also INFECTIOUS NASAL GRANULOMATA IN CATTLE; RHINOSPORIDIOSIS; RHINOTRACHEITIS, INFECTIOUS BOVINE.) Nosocomial Hospital-acquired Human nosocomial infections, usually associated with medical or surgical interventions, affect about to per cent of hospital patients, i.e about million people in the USA alone, resulting in some million excess hospital bed-days About per cent of the victims die Nostril (see NOSE) Nostril Flies (Oestridae) Nostril flies (oestridae) are members of the class of 2-winged flies, whose larvae are parasitic in the nasal cavities, and in the air sinuses of the skull, of sheep (See under FLIES.) Notifiable Diseases Notifiable diseases are those which, when they occur upon farm premises, must be notified to the Divisional Veterinary Office of the State Veterinary Service of the Department of the N 490 Notoedric Mange Environment, Food and Agriculture (DEFRA) The list of notifiable diseases is amended from time to time and usually applies to all member states of the European Union Those which are notifiable in the UK but not in all other member states are identified by an asterisk in the list below N Teschen disease Tuberculosis (bovine) Tuberculosis (deer) Varroasis (in bees) Vesicular stomatitis Viral haemorrhagic septicaemia (in fish)* Warble fly (bovine)* African horse sickness African swine fever American foul brood (bees) Anthrax Aujeszky’s disease* Avian influenza Bluetongue Bonamiasis (in shellfish)* Bovine spongiform encephalopathy (BSE) Brucella melitensis Brucellosis (bovine) Cattle plague (rinderpest) Classical swine fever Contagious agalactia Contagious bovine pleuropneumonia Contagious epididymitis Contagious equine metritis Dourine Enzootic bovine leukosis Epizootic haemorrhagic virus disease (deer) Epizootic lymphangitis Equine infectious anaemia Equine viral arteritis Equine viral encephalomyelitis (Eastern, Western and Venezuelan) European foul brood (bees) Foot-and-mouth disease Furunculosis (fish) Glanders and farcy Goat pox Gyrodactylosis caused by Gyrodactylus solaris* Haplosporidiosis (in fish) Infectious haematopoetic necrosis (in fish) Infectious salmon anaemia* Iridovirosis (in fish) Lumpy skin disease Marteiliosis (in shellfish)* Mikrocytosis (in fish) Newcastle disease Paramyxovirus in pigeons Perkinosis Peste des petits ruminants Rabies Rift Valley fever Scrapie Sheep pox Spring viraemia of carp* Swine vesicular disease (SVD) The following are notifiable diseases in the whole of Ireland (north and south): Brucellosis, in ruminating animals and swine Caprine viral arthritis-encephalitis Caseous lymphadenitis Enzootic abortion of ewes Fowl typhoid Infectious bovine rhinotracheitis Johne’s disease Maedi/visna Mycoplasmal (infectious) synovitis Mycoplasmosis (M gallisepticum or M, melea gridis) Parasitic mange of horses Porcine epidemic diarrhoea (coronavirus) Porcine respiratory and reproductive syndrome (PPRS; Blue ear disease) Pullorum disease Pulmonary adenomatosis Psittacosis Salmonellosis Transmissible gastroenteritis of pigs Tuberulosis in ruminating animals Turkey rhinotracheitis In Northern Ireland only: Duck plague Fowl pox Infectious laryngotracheitis Trichinosis Vesicular exanthema In the Republic of Ireland only: Avian yersiniosis Campylobacteriosis (See under DISEASES OF ANIMALS ACTS – Diseases of Fish Act 1937 (as amended 1983), Diseases of Fish (Control) Regulations1994 and the Fish Health Regulations 1997 for duties and responsibilities of animal-owners.) Notoedric Mange (see under MITES) Nsaids Nsaids is an acronym for Non-Steroidal, Analgesic, anti-Inflammatory Drugs They are Nursing of Sick Animals very widely used in the control of postoperative pain, arthritis, joint pain, and inflammatory oedema; also as anti-inflammatory agents where pain may not be an issue and steroids are best avoided Flunixin, paracetamol, phenylbutazone, ketoprofen, and aspirin are examples of NSAIDs They may be administered orally or by injection according to type and formulation There are restrictions on the use of most NSAIDs in horses competing under Jockey Club, etc., rules Nuclear Magnetic Resonance (NMR) Also known as magnetic resonance imaging (MRI), this is a hazard-free, non-invasive technique for generating images of internal sections of the body The system works by utilising the differing absorption of radio waves by atoms in the body when exposed to a magnetic field The amount of absorption is measured and the data used to generate a computer image Nuclear Medicine Involves the use of radio-isotopes for diagnosis and therapy (See RADIO-ISOTOPES.) Nuclear Weapons (see under RADIOACTIVE FALL-OUT) Nucleic Acids (see DNA and RIBONUCLEIC ACID.) Nuclein Nuclein is a protein substance containing phosphorus derived from the nuclei of cells Nucleotides 491 home for nursing There is likely to be less stress for your pet when it is not sent or kept away from its familiar surroundings A dog or cat which is ill, or recovering from an operation or accident, tends to seek solitude and require peace Continual fussing and interference, however well-meant, are to be avoided (This is something which has to be impressed on children.) Fresh air, warmth, and an absence of bright lights and noise (such as those emanating from a TV set) are desirable A patient with eye inflammation, tetanus, or some other nervous system disorder needs protection from bright light In many cases, it is helpful to put down old newspaper, which can be burnt after use If a dog cannot go outside, a box of earth or ashes, or the material sold for cat trays, may be useful too An extra sanitary tray will be needed for an ill cat under these circumstances Constipation may be a problem A little of the oil from a tin of sardines may be taken voluntarily (Remember that a cat straining ineffectually over a litter tray may be trying to pass urine and not faeces.) Temperature-taking often forms a part of animal nursing Buy a clinical thermometer with a stout, stubby end, and lubricate the latter before passing it into the rectum Cooking oil will serve for this purpose An improvised jacket, with holes for the front legs, is useful in cases of bronchitis or pneumonia Never omit to wipe away the discharges from the eyes and nose of an ill animal It is sometimes difficult to keep an ill dog or cat clean Any hair or fur which becomes soiled should be cut away, and the part washed (see RADIO-ISOTOPES) Nucleus The central body in a cell which controls its activities (See CELLS.) Nursing of Sick Animals The advent of qualified professional VETERINARY NURSES has been of great benefit to practising veterinary surgeons, especially those engaged in small-animal practice, and to their patients; and has facilitated measures for intensive care Nursing of small animals at home If your dog or cat has an infectious disease, nursing will have to be undertaken at home, since veterinary hospitals usually cannot accept such cases owing to the risk to other patients In other cases, after initial veterinary treatment, it is often preferable to have the animal at Feeding Prescription diets are specially formulated for use in assisting the treatment of specific canine and feline disorders They are available in canned and dry form, as prescribed by veterinary surgeons; see DIET AND DIETETICS Human invalid foods (e.g Complan) are often useful Do not force solid foods on a sick animal which, if suffering from a digestive upset, is usually better off without solid food for a day or two (See also under VOMITING.) Variety is important in feeding the sick During convalescence the animal may be tempted to eat by offering small quantities of warmed proprietary food or meat jelly, minced liver or rabbit, or sardine Nursing of horses The affected horse should be removed from its stall in the stable N 492 Nutrition, Faulty and placed in isolation It should have plenty of bedding, be provided with clean water, and if the weather is cold it should be clothed with a rug In cases where the horse is unable to stand, a specially thick straw be should be given, and one or two bags filled with straw, or bales of hay, are useful to prop it up in an upright position on the breast Horses that are down must be turned over on to the other side twice or thrice daily The rectum and bladder may require evacuation artificially, if it does not occur naturally If bed sores appear, they should be dressed twice daily with surgical spirit, and more bedding should be supplied In respiratory diseases the most important factor in nursing is the adequate provision of fresh air Small feeds should be offered several times daily, and when a horse refuses one type of food it should be offered another Whenever the breathing is faster than normal drenching should be avoided N Nursing of cattle Isolate in a loose-box Calves should be shut alone in a pen The same conditions as to bedding, clothing, water, ventilation, etc., apply to cattle as to horses Patient kindly treatment, the avoidance of all unnecessary fuss and haste, and a gentle firmness are essential A sick cow which refuses hay from a new ley will often eat hay from old pasture Molasses may add palatability to food otherwise rejected; so may a little salt Nutrition, Faulty Nutrition, faulty can lead to disease and losses of farm animals Examples are nutritional muscular dystrophy (see under MUSCLES, DISEASES OF); blindness as a result of vitamin A deficiency (see EYE, DISEASES OF); poisoning by excessive fluorides in the diet (see FLUOROSIS); and an all-muscle meat diet can lead to CANINE and FELINE JUVENILE OSTEODYSTROPHY (See also ‘CAT, ANGRY’ POSTURE.) Nutritional Myopathy A condition resulting from a deficiency of vitamin E or selenium (See MUSCLES, DISEASES OF; PARALYTIC MYOGLOBINURIA; SUDDEN DEATH.) Nuttallia Nuttallia is the name given to a genus of piroplasms which cause biliary fever in horses in many parts of the world There are forms involved – Babesia (Nuttallia) equi, which is the smaller and more important, and B (Nuttallia) caballi Each is transmitted by one or more ticks (See BABESIA – Babesiosis.) Nux Vomica Nux vomica is the seed of the Strychnos nuxvomica, an East Indian tree It has intensely bitter taste The medicinal properties are due to alkaloids – strychnine and brucine, which the plant contains Brucine has an action similar to, though much weaker than, strychnine (See under STRYCHNINE.) Nyctalopia or Night-Blindness (see EYE, DISEASES OF) Nymphomania A condition in which a female animal is (or behaves as if ) in constant oestrus It is associated with pathological changes, often of a cystic nature, in the ovaries Hormone treatment may be tried under veterinary advice; or removing the ovaries by surgical measures, as early as possible after the erotic symptoms have made their appearance (See OVARIES, DISEASES OF; HORMONE THERAPY.) Nystagmus Nystagmus is a condition in which the eyeballs show constant fine jerky movements of an involuntary nature  ... point or area where neuron is able to make contact with another; the contact being between the axon of neuron and a dendrite of another neuron, or between the axon of neuron and the cell of another... animal-owners.) Notoedric Mange (see under MITES) Nsaids Nsaids is an acronym for Non-Steroidal, Analgesic, anti-Inflammatory Drugs They are Nursing of Sick Animals very widely used in the control... etc., rules Nuclear Magnetic Resonance (NMR) Also known as magnetic resonance imaging (MRI), this is a hazard-free, non-invasive technique for generating images of internal sections of the body